1. Field of the Invention
The present invention relates to a photometry device of a camera for obtaining a proper exposure control value by photometrically measuring an object.
2. Related Background Art
As shown in FIG. 15, a conventional photometry device performs exposure control using a photometry element having spectrum sensitivity characteristics having a sensitivity peak near a wavelength of 550 nm.
Since a photometry element having the above-mentioned spectrum sensitivity characteristics has a sensitivity peak in a green region of R (red), G (green), and B (blue) as three primary colors of light, it can provide excellent exposure to an achromatic object or a green object. However, such a photometry element recognizes an object in a color close to a primary color such as red, blue, or the like to be a dark object since it has a low sensitivity to these colors.
For this reason, when an object including many red or blue components is taken, the photometry element overexposes as compared to the actual sensitivity of a color film, and as a result, a taken photograph is overexposed, resulting in a photograph with poor color reproducibility.
For example, when a scene, e.g., a dusk scene including many red components, is taken, since a conventional photometry element has a low sensitivity to red components, an overexposure occurs, and a photograph with poor red reproducibility is obtained as if a daytime scene were taken.
It is an object of the present invention to provide a photometry device of a camera, which can prevent an overexposure of an object including many single color components such as red, blue, and the like, and has good reproducibility of colors.
A photometry device of a camera according to the present invention comprises a photometry element for photometrically measuring an object while dividing object light into a plurality of color components, and exposure control means for calculating an exposure control value on the basis of a plurality of photometry outputs corresponding to the color components of the photometry element.
In the arrangement of the present invention, the photometry element divides object light into a plurality of color components, e.g., R, G, and B three primary color components, and performs level detection in units of color components. The exposure control means selects, as an exposure control value, a color component of a maximum level from photometry outputs of the color components measured by the photometry element, and performs exposure control by calculating an aperture value, a shutter speed, and the like on the basis of the selected exposure control value. For this reason, even when a scene including many single color components such as red, blue, and the like is taken, a photograph with good color reproducibility can be obtained without causing an overexposure.
Alternatively, a value obtained by weighting a plurality of photometry outputs corresponding to the color components and adding the weighted outputs may be selected as an exposure control value. In this case, it is preferable to preponderantly weight a maximum one of the plurality of photometry outputs.
Another photometry device of a camera according to the present invention comprises photometry means for dividing a photographing field into a plurality of areas, and photometrically measuring objects in the divided areas while dividing corresponding object light into a plurality of components, and exposure control means for calculating an exposure control value on the basis of a plurality of photometry outputs from the photometry means. The photometry means divides object light into a plurality of color components, e.g., R, G, and B three primary color components for each of areas obtained by dividing a photographing field, and performs level detection in units of color components. The exposure control means selects color components of maximum levels of the respective divided areas from the photometry outputs of the color components measured by the photometry means to determine an exposure control value, and performs exposure control by calculating an aperture value, a shutter speed, and the like on the basis of the determined exposure control value. For this reason, even when a scene including many single color components such as red, blue, and the like is taken, a photograph with good color reproducibility can be obtained without causing an overexposure.
Alternatively, a value obtained by weighting photometry outputs corresponding to the color components and adding the weighted outputs for each divided area may be selected as a representative value of the corresponding area, and an exposure control value may be calculated on the basis of a plurality of representative values obtained. In this case, it is preferable to preponderantly weight a maximum one of the photometry outputs in each divided area.